hey D lemme add that I am a huge fan , i cant get into the different modes yet for I am still familiarizing myself with the one everyones used to (been playing 2 years) but the way you describe it makes me think you are an author of grateful dead books... or should be,,, and this thread really has my attention

I wanna solo like jerry and bob man and I think you can help me a lot.

I was using that riff the other night on NFA, but also playing the 1st string/5th fret - so it was like a E7add6 (?) to A progression. Sounded pretty cool - it's nice to try and spice up simple songs like that.

With only one note changed the B and D strings hold the continuity while the G string exhibits the chord change.
The E form voices two 5ths and a 1st. The B voices two 1's and a 5th. Something to ponder.

Hey Kenny,
What's interesting about Bob is when he does use power chords it's almost the antithesis of what they are. Instead of foresaking the third to get that hard rock, driving sound, he's looking to minimize (his "thiness" comes to mind) for a smoother transition from chord to chord. Almost like he hasn't even changed chords. I hear this again and again and the shapes above are my attempt at replicating that sound. I'll have to check some video.

A sus4 kind of fits into this picture. A subtle one note change to reflect say D (the 4th of A) while holding the A chord.

Me thinks he may be using these "power chord" shapes more than you think. Of course I may be wrong. Thanks for responding.

I've spent the better part of ten years studing Bob Weir among others.
Bob often uses barre chords, but not for power. His frequent us of the barre is to keep the song clean. often when their are many members in the band, full chords can be to overbearing and can take away from the other instruments in the mix. tonality is also a big part of it also. different barre chords highlight different notes.I'll give a few examples using West L.A. Fadeaway.
heres the main lick in it's simplest form
Am
E-------------------------------------
B-------------------------------------
G-------5-5---------------------------
D-7-5-7------7-7-5-5------------------
A--------------------7-7-5-5---5------
E----------------------------8---8-5--

when playing this in chord form it's very important that you accent the C at the end of phrase one. I found the best way to do this is by sliding from the standard Am Barre to a higher version featuring the C more prominantly.
Am Am/C Am
E-5-5-5-5-5--8--8---5-5-5-5-----------------
B-5-5-5-5-5-10-10---5-5-5-5-5-5-5-5---------
G-5-5-5-5-5--9--9---5-5-5-5-5-5-5-5---------
D-7-7-5-5-7/10-10---7-7-5-5-5-5-5-5---------
A---------------------------7-7-5-5---5---7-
E-----------------------------------8---8-5-